Railway-traffic-controlling apparatus



March 31, 1931.

H. THOM PSON RAILWAY TRAFFIC CONTROLLING APPARATUS Filed July 19, 1928 H0 X If v INVENTORI fffLT/narnpdon,

Patented Mar. 31, 1931 UNITE TES HOWARD A. THOMPSON, OF EDGEWOOD BOROUGH, EENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH 8:7 SIGNAL GOIVIPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORA- TION OF PENNSYLVANIA RAILWAY-TRAFFIC-CONTRQLLING APPARATUS Application filed July 19, 1928. Serial N'o. 293,958.

My invention relates to railway traffic controlling apparatus, and particularly to apparatus of the type involving train-carried governing mechanism controlled by train governing current in the track rails. More specifically the present invention relates to thetrackway portion of such apparatus, and has for an object the provision of means for obtaining recurrent acknowledgment of successive stop signals by delaying the application of train governing current to the track rails when a train enters a section the signal for which indicates stop.

I will describe two forms of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a diagrammatic view showing one form of apparatus embodying my invention, and Fig. 2 is a view showing a modification of portions of the apparatus shown in Fig. 1 and also embodying my invention.

Referring first to Fig. 1, the reference characters 1 and 1 designate the track rails of a railway track along which traffic normally moves in the direction indicated by the arrow. These rails are-divided by insulated joints 2 intoa plurality of sections of which only one complete section C-D is shown in the drawing.

The section CD is provided with a track circuit comprising a battery 3 connected across the rails at the exit end of the section through a reactor 4, a resistance 5, and the secondary of a transformer A. A direct current track relay T is connected across the rails at the entrance end of the section, and this relay is, of course, responsive to track circuit current furnished by the battery 3.

An insulated joint 2* is interposed in the rail 1? at an intermediate point in the section relay F.

Section C D is provided with a signal S which signal is controlled by a front contact 8 of a signal relay H through a circuit which is obvious from the drawing. It is understood that the reference characters B and O designate the terminals of a source of current which furnishes the energy for the operation of the signal. Relay H is provided with a circuit which passes from terminal B, through a contact E front contact 6 of relay F, front contact 7 of relay T and the winding of relay H to terminal 0. Contact E is operated by a manually operable lever in an interlocking machine which will usually be located in a tower adjacent the section CD. Contact E is normally open, so that signal S normally indicates stop, but but when contact E is closed signal S will give a proceed indication if and only if both of the track relays T and F are energized. Signal S will also usually be controlled by traffic conditions in advance of section CD, but the apparatus for accomplishing this control is omitted from the drawing, because it forms no part of my present invention.

It will be seen from the foregoing that track relays T and F are both normally energized by current from battery 3, but that when a train enters section C-D it immediately de-energizes relay T and it later de- 20, which are periodically closed at different rates while the device is energized. The coding device Z is controlled by a coder relay K in such manner that when the relay is deenergized the coding devcie is likewise deenergized and so is at rest. When the coder relay K is energized, the coding device Z is also energized by virtue of a circuit which passes from terminal X of a source of alternating current through front contact 18 of relay K and the winding of coding device Z to termi nal Y of the same source of current. When the coder relay K is energized, alternating current is supplied to the primary of transformer A, through contact 19 or 20 according as signal relay H for the section next in advance of point D is de-energized or energized. Assuming that relay H is energized, the circuit for the primary of transformer A is from terminal X, through contact 18 of coder relay K contact 20 of the coding device Z front contact 21-21 of relay H and the primary of transformer A to terminal Y. If relay H is (lo-energized, the circuit is the same except that it includes contact 19 of the coding device Z and back contact 21-2l of relay H Coder relay K is provided with a pick-up circuit which passes from terminal B, through back contact 9 of track relay T wire 10, contact N wires 11 and 12, and the winding of relay K to terminal O. Contact N is operated by signal S and is closed when this signal gives aproceed indication, but is open when this signal indicates stop. This pick-up circuit is provided with a branch around contact N", which branch includes back contact 16 of the auxiliary track relay F and wire 17. Relay K is provided with a stick circuit which passes from terminal B through back contact 9 of relay T wire 13, front contact 14 of relay K wire 15 and the winding of relay K to terminal 0. It fol lows from the forgoing, that when a train enters section C-D, relay K immediately becomes energized if signal s indicates proceed, but that if signal S indicates stop the energization of relay K is delayed until relay F becomes de-energizecl. lVhen relay K does become energized, it remains energized by virtue of its stick circuit as long as track relay T remains de-energized.

The apparatus shown in Fig. l is suitable for cooperation with train-carried governing means requiring the supply of periodically interrupted alternating current to the track rails to prevent a stop indication of any suitable kind, such as an automatic application of the brakes. If the supply train governing current is discontinued, a stop indication will result unless the engineman takes proper action to acknowledge the change in trafiic conditions. If he does acknowledge, the train may proceed without incurring a stop indication, but if train governing current is again supplied to the rails and this current is subsequently discontinued, the engineman must again acknowledge to prevent a stop indication. One form of train-carried governing means operating in this manner and suitable for co-operation with the trackway apparatus herein disclosed, is shown and s ribed in application for Letters Patent or the United States filed by Lloyd V. Lewis on August 2, 1927, Serial No. 210,165, for Railway traiiic controlling apparatr The operation of the apparatus shown in Fig. 1 is as follows: Assuming first that signal S is in one of its proceed positions when a train enters section C-D, the coder relay K will be set into operation at once, and so the train will be supplied with alternating train governing current periodically interrupted at one frequency or the other, depending on trailic conditions in advance of this section. This coded current passes freely around oint 2 through rectifier G and relay F, and so reaches the train while the train is between point C and joint 2. If, however, signal S indicates stop when the train enters section C-D, the supply of train govern ing current will be delayed until the front axle of the train reaches insulated joint 2, and so a stop indication will be given abroad the train unless the engineer takes suitable action to acknowledge the stop indication of signal S This operation will be repeated at each successive signal if the signal indicates stop.

The distance between point C and the insulated joint 2 should be at least suflicient to insure that the highest speed train will consume enough time in traveling this distance to decnergize the de-coding relay which forms part of the locomotive equipment. In actual practice the minimum for this distance will probably be about 300 feet. It should be understood, however, that the distance between C and 2 might be made the entire length of the track section less a short distance of approximately 300 feet, in which case the train would receive no train governing energy throughout the greater portion of the track section, and the distance between the insulated joint and point D would constitute a short re-set section to guarantee recurrent acknowledgment of signal S if the latter signal should be in the stop position.

Referring now to Fig. 2, I have in this view shown the modifications required when the track circuit energy is alternating current instead of direct current. In Fig. 2 when the coder relay K is de-energized, alternating track circuit current is continuously supplied to the primary of transformer A through the back point of contact 27 of this relay, whereas when relay K is energized, periodically interrupted alternating current is supplied to the primary of transformer A through the front point of contact 27 and either contact 19 or 20 of the coding device H depending on whether relay H is de-energized or energized. The auxiliary track relay, which is here designated F has a winding 24 which i s connected with the rail 1 through an autotransformer 26, the primary terminals of which are connected with this rail on opposite sides of the insulated joint 2 and the secondary terminals of which are connected with relay winding 24. Relay F also has a second winding 25 constantly supplied with alternating current from terminals X and Y.

The main track relay, which is here designated T comprises a winding 22 connected across the track rails, and a second winding 23 supplied with alternating current from the terminals X and Y. As shown in Fig. 1, the track circuit current and the train governing current are of the same frequency. When one frequency is used for track circuit current and a different frequency for train governing current, the windings 23 and 25 of the track relays are preferably controlled in such manner that these windings receive current of the track circuit frequency when track circuit current is being supplied to the track rails, and current of train governing frequency y when train governing current is being supplied to the track rails. This feature has nothing to do with my present invention, however, and consequently, it is not illustrated in the accompanying drawing. One means for accomplishing this control of the track relay. windings 23 and 25 is illustrated in Letters Patent of the United States No. 1,632,162, granted to C. R. Beall on June 14;, 1927, for Railway traffic controlling apparatus.

Although I have herein shown and described only two forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a section of railway track, a source of track circuit current at the exit end of said section and a main track relay connected across the track rails at the entrance end of said section, an insulated joint in one track rail at an intermediate point in said section, an auxiliary track relay connected with said one rail on opposite sides of said joint, a signal for said section controlled in partby said two track relays, and means controlled jointly by said signal and said two track relays for supplying train governing current to the rails of said section.

2. In combination, a section of railway track, a source of track circuit current at the exit end of said section and a main track relay connected across the track rails at the entrance end of said section, an insulated joint in one track rail at an intermediate poin in said section, an auxiliary track relay connected with said one rail on opposite sides of said joi: a signal for said section controlled in part by said two track relays, a contact operated by said signal and closed when the signal indicates proceed but not when it indicates stop, a coder relay, a pickup circuit for said coder relay including a back contact of said main track relay and said signal operated contact, a branch around said signal operated contact in said pick-up circuit including a back contact of said auxiliary track relay, a stick circuit for said coder relay including a front contact of the coder relay and a back contact of said main track relay, and means for supplying train governing current to the rails of said section when said coder relay is energized.

3. In combination, a section of railway track, a source of track circuit current at the exit end of said section and a main track re lay connected across the track rails at the entrance end of said section, an insulated joint in one track rail at an intermediate point in said section, an auxiliary track relay con nected with said one rail on opposite sides of said oint, a signal for said section controlled in part by said two track relays, and means controlled by said relays and said signal for supplying train governing current to the rails of said section as soon as a train enters the section if said signal indicates proceed but for delaying the supply of such current until the train reaches said insulated joint if the signal indicates stop.

4. In combination, a section of railway track, a source of track circuit current at the exit end of said section and a main track relay connected across the track rails at the entrance end of said section, an insulated joint in one track rail at an intermediate point in said section, an auxiliary track relay connected with said one rail on opposite sides of said joint, a signal for said section, a circuit for said signal controlled by said two track relays and by a manually operable lever in an interlocking tower, and means controlled by said relays and said sig nal for supplying train governing current to the rails of said section as soon as a train enters the section if said signal indicates proceed, but for delaying the supply of such current until the train reaches said insulated joint if the signal indicates stop.

5. In combination, a section of railway track, a source of track circuit current at the exit end of said section and a main track relay connected across the track rails at the entrance end of said section, an insulated joint in one track rail at an intermediate point in said section, an auxiliary track relay connected with said one rail on opposite sides of said joint, a signal for said section controlled jointly by said two track relays, and means controlled jointly by said signal and said track relays for supplying periodically interrupted"alternating train governing current to rails of said section.

6. In combination, a section of railway track, a source of track circuit current at the exit end of said section and a main track relay connected across the track rails at the entrance end of said section, an insulated joint in one track rail at an intermediate point in said section, an auxiliary track relay connected with said one rail on opposite sides of said joint, a signal for said section controlled by said track relays, and means controlled jointly by said signal and said relays for supplying the rails of said section with alternating train governing current periodically interrupted at one frequency or another according to traffic conditions in ad Vance of said section.

7. In combination, a section of railway track, an alternating current track circuit for said section including a track relay connected across the rails at the entrance end of the section, an insulated joint in one track rail at an intermediate point in said section, an autotransformer having its primary terminals connected with said one rail on the 0pposite sides of said joint, an auxiliary alternating current track relay having a winding connected with the secondary terminal of 20 said transformer, and means controlled jointly by said main and auxiliary track relays for supplying periodically interrupted alternating train governing current to the rails of said section. 23 In testimony whereof I afiix my signature.

HOW WARD A. THOMPSON. 

